Abstract
PURPOSE: The purpose of this study was to evaluate the in-gel strain and tear reduction provided by 2 skin protectant products that were applied as a liquid and allowed to dry, leaving behind a protective layer.
DESIGN: Prospective, 3-group comparison cohort study using an in vitro model.
METHODS: A fragile agar-based gel with an embedded bead was used in a custom device that applied variable interface pressures of 550, 1080, or 1600 Pa, respectively. The device then imparted 216 N of external shear force in 0.625-mm increments. The resulting strain in the gel was measured by digital image correlation. The strain at tearing was determined by observing the images of the gels and calculating the strain at that point. This approach was used to compare untreated gels to gels treated with one of 2 commercially available cyanoacrylate-based skin protectants. The results from the 3 groups were first analyzed by analysis of variance, followed by Tukey's Honestly Significant Difference test when indicated.
RESULTS: We observed a proportional increase in interface pressure and strain that differed among the 3 groups. Specifically, the gels treated with a mixed polymer skin protectant had less pretearing strain than the control gel at both the 1080-Pa load (-15%, P = 3.64 x 10-4) and 1600 Pa-load (-20%, P = .03). The pure cyanoacrylate-treated gels had less strain than the control at 1080 Pa (-34%, P = 4.25 x 10-7) and 1600 Pa (-48%, P = 1.07 x 10-7); it also had less strain than the mixed polymer product at 1080 Pa (-19%, P = 5.38 x 10-6) and 1600 Pa (-28%, P = 3.88 x 10-3). In terms of protection from tearing, at an interface pressure of 1080 Pa, the control gel tore 80% of the time, the mixed polymer-treated gel tore 100% of the time, and the pure cyanoacrylate-treated gel did not tear (0/5, P = 8.84 x 10-5). Under a load of 1600 Pa, 100% of the control and mixed polymer-treated gels tore while none of the cyanoacrylate-treated gels did (P = 2.54 x 10-24).
CONCLUSION: The pure cyanoacrylate-based skin protectant provided the most protection, with consistent reductions in both strain and tearing. Both skin protectants reduced the initial in-gel strain; however, only the pure cyanoacrylate-treated product protected the gel from tears under the conditions tested. These results indicate that cyanoacrylate-based skin protectants can reduce shear strain and tearing in fragile elastic materials.